Fix PcDescriptor iteratot to never return a pointer to a memory location since the data can move wi…

runtime/vm/stack_frame.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/stack_frame.h"
 
 #include "vm/assembler.h"
 #include "vm/deopt_instructions.h"
 #include "vm/isolate.h"
 #include "vm/object.h"
@@ skipping 208 matching lines @@
   if (handlers.Length() == 0) {
     return false;
   }
 
   // Find pc descriptor for the current pc.
   REUSABLE_PC_DESCRIPTORS_HANDLESCOPE(isolate);
   PcDescriptors& descriptors = reused_pc_descriptors_handle.Handle();
   descriptors = code.pc_descriptors();
   PcDescriptors::Iterator iter(descriptors, RawPcDescriptors::kAnyKind);
   while (iter.HasNext()) {
-    const RawPcDescriptors::PcDescriptorRec& rec = iter.Next();
+    RawPcDescriptors::PcDescriptorRec rec;
+    iter.NextRec(&rec);
     if ((rec.pc() == pc()) && (rec.try_index() != -1)) {
       RawExceptionHandlers::HandlerInfo handler_info;
       handlers.GetHandlerInfo(rec.try_index(), &handler_info);
       *handler_pc = handler_info.handler_pc;
       *needs_stacktrace = handler_info.needs_stacktrace;
       *has_catch_all = handler_info.has_catch_all;
       return true;
     }
   }
   return false;
 }
 
 
 intptr_t StackFrame::GetTokenPos() const {
   const Code& code = Code::Handle(LookupDartCode());
   if (code.IsNull()) {
     return -1;  // Stub frames do not have token_pos.
   }
   const PcDescriptors& descriptors =
       PcDescriptors::Handle(code.pc_descriptors());
   ASSERT(!descriptors.IsNull());
   PcDescriptors::Iterator iter(descriptors, RawPcDescriptors::kAnyKind);
   while (iter.HasNext()) {
-    const RawPcDescriptors::PcDescriptorRec& rec = iter.Next();
+    RawPcDescriptors::PcDescriptorRec rec;
+    iter.NextRec(&rec);
     if (rec.pc() == pc()) {
       return rec.token_pos();
     }
   }
   return -1;
 }
 
 
 
 bool StackFrame::IsValid() const {
@@ skipping 219 matching lines @@
     if (deopt_instr->kind() == DeoptInstr::kCallerFp) {
       return (index - num_materializations_);
     }
   }
   UNREACHABLE();
   return 0;
 }
 
 
 }  // namespace dart